The present invention relates to a pneumatic tire having a tread pattern including at least three circumferential grooves extending in a tire circumferential direction.
It is known that, in a tire, a tire noise reduction performance and a traction performance (on-snow performance) on a snow-covered road are antinomic performances.
In order to achieve a reduction in tire noise, it is common practice to reduce a tire groove area, in particular, a groove area of lug grooves extending from tire circumferential main grooves and inclined in a width direction with respect to the circumferential tire main grooves. However, in order to achieve an improvement in on-snow performance, it is common practice to increase the groove area of the lug grooves, with the result that a reduction in tire noise and an improvement in on-snow performance have been regarded as being mutually incompatible. In particular, regarding a tire for a sport utility vehicle (SUV) and an all-season tire provided for comfortable traveling on muddy roads and snow-covered roads and for comfortable traveling on dry roads, there is a demand for compatibility between the reduction in tire noise and securing of the requisite on-snow performance.
In this context, JP 2710341 B discloses a pneumatic tire in which tire blocks are arranged alternately with respect to circumferentially adjacent blocks.
More specifically, JP 2710341 B discloses a tire in which, as illustrated in FIG. 2 of JP 2710341 B, blocks 32X and blocks 32Y adjacent thereto are offset with respect to each other in the tire width direction.
However, in the above-mentioned pneumatic tire, it is not always possible to attain such reduction in tire noise and such an improvement in on-snow performance as described above.
In view of the above-mentioned problem in the prior art, it is an object of the present invention to provide a pneumatic tire capable of attaining both a reduction in tire noise and an improvement in on-snow performance and, in particular, a pneumatic tire having a feature in terms of a pattern.
A pneumatic tire according to the present invention has a tread pattern which comprises at least three circumferential grooves with a groove width of 6 to 18 mm and a groove depth of 6.0 to 16.0 mm extending in a tire circumferential direction, wherein, on groove walls on both sides forming the at least three circumferential grooves, first inclined walls inclined by an inclination angle of 5 to 20 degrees with respect to the tire circumferential direction and second inclined walls inclined by an inclination angle of 0 to 45 degrees with respect to a tire width direction are provided so as to be successively connected in the tire circumferential direction so that positions of groove ends in the tire width direction vary in the tire circumferential direction, connecting portions between the first inclined walls and the second inclined walls being bent in a V-shape in a plan view of the tread pattern, a length of the first inclined walls being larger than a length of the second inclined walls, every two of the first inclined walls on both sides of each of the second inclined wall having a step amount of 1.5 to 5.0 mm in the tire width direction, three to five pairs of the first inclined walls and the second inclined walls adjacent to each other being provided for one tread pattern.